JP2000188448A - Wiring substrate and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease a loop area formed of high frequency power supply current without mounting a part such as a capacitor for restraining radiation noise. SOLUTION: A multilayer substrate 1 is provided with a via 8 and a decoupling capacitor is practically formed of an extension part 7a of a power supply wiring 7 formed in an inner wall of the via 8 and a conductor 11 plugging a central hole 9 of the via 8 and is connected to a ground wiring 5. As a result, it is possible to decrease an area of a current loop and to restrain radiation noise effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wiring (printing).
The present invention relates to a substrate and a method for manufacturing the same.

[0002]

2. Description of the Related Art Transistors, ICs (integrated circuits), LS
Radiation noise generated from a multilayer wiring board on which a circuit element such as I (large-scale integrated circuit) is mounted is classified into common mode noise and normal mode noise. It is generally said that the former has a large influence. The common mode noise mainly refers to radiation caused by a high-frequency current flowing into a power supply line or a ground (GND wiring).

FIG. 6 is a schematic diagram for explaining radiation noise generated by a loop current. As shown in this figure,
The path of the current I1 flowing through the signal pattern from the driver 101 to the receiver 103 forms a loop (return loop) with the path of the return current (return current) I2. Assuming that the area of this loop is S, the distance in the vertical direction from the loop surface is r, and the frequency of the signal is f, the electric field E [V / m] radiated in the vertical direction from the loop surface is It is expressed by an equation.

E = 1.316 × 10 ⁻¹⁴ × | I | f ² S (1 / r) [V / m] (1) where | I | = | I1 | = | I2 |

From equation (1), it can be seen that the radiation noise increases in proportion to the frequency f, the current I, and the loop area S. Of these, the frequency f and the current I are simply determined by the system restrictions. It can not be changed. Therefore, in order to actually suppress radiation noise, it is necessary to reduce the loop area S as much as possible.

FIG. 7 is a schematic diagram showing radiation noise generated by a power supply current generated near the IC (however, a capacitor is connected in parallel with the IC 105 to reduce noise due to a high-frequency current as described below). Let me do). I
A current path until the current generated from the power supply (pin) of the C105 is dropped to the GND (pin) wiring side, or a loop area S formed by the reverse current path, is also radiated in proportion to the magnitude as described above. It can be said that the noise increases. That is, not only in the system shown in FIG. 6, but also in the case shown in FIG. 7, it is necessary to reduce the loop area S in order to suppress radiation noise. For this reason, countermeasures as shown in FIGS. 8 and 9 have conventionally been taken for wiring boards.

First, FIG. 8A is a plan view schematically showing an example of the structure of a conventional wiring board, and FIG. 8B is a sectional view thereof.

The wiring board of this example has four signal layers 111.
And three ground layers 113 and one power supply layer 115,
Each of these is an eight-layer printed circuit board laminated with an insulating material 117 interposed therebetween. On top of the uppermost signal layer 111, IC1
19 and capacitors 100 and 200 are mounted, and IC1
The 19 power supply terminals 121 are connected to the power supply layer 115 by via holes 120. The ground terminal 123 of the IC 119 is connected to the ground layer 113, and the other ends of the capacitors 100 and 200 are also connected to the ground layer 113.

As described above, the decoupling capacitor 100 is connected between the power supply line of the power supply layer 115 of the wiring board and the ground line of the ground layer 113, and is connected to the vicinity of the IC 119 which is a high-frequency power supply current generation source. It is common practice in the industry to connect in parallel. This means that the high-frequency power supply current flowing through the power supply layer 115 due to the switching operation of the IC 119 is
This is to bypass the capacitor C near the capacitor 119 via the capacitor 100 and to suppress a potential change of the power supply terminal 121 due to the switching operation of the IC 119.

A power supply layer 115 serving as a power supply line is
For the purpose of reducing the resistance value and suppressing the voltage fluctuation of the DC power supply, the conductor is formed of a conductor whose wiring width is much wider than that of general wiring.

Next, FIG. 9A is a plan view schematically showing the structure of another example of a wiring board (Japanese Patent Application No. 10-198584), and FIG. 9B is a sectional view thereof.

The wiring board includes a terminal 223 for connecting a plurality of power supply wires and mounting a plurality of capacitors 300, and an output-side wire c having one end connected to the terminal 223 for outputting a high-frequency power supply current. A ground layer 113 disposed above or below the output-side wiring c, and a portion 2 provided on the ground layer 113 and having a wider width than the output wiring c along the wiring 2.
25, a wire b connected to the other end of the output side wire c and having a width larger than the width of the hollow portion 225, and mounted on a connection portion between the wire b and the other end of the output side wire c. And a condenser 400. This wiring board also attempts to reduce a loop area formed by a path through which a high-frequency power supply current (generated in the power supply layer) flows through a capacitor.

[0013]

As is apparent from the above description, in the conventional wiring board, it is necessary to mount components such as capacitors in order to reduce the loop area. Therefore, component cost and mounting cost are required. Also, since these components are mounted on the surface layer of the wiring board, it is not suitable for flattening (solid layering) the surface layer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a wiring board and a circuit board capable of reducing a loop area formed by a high-frequency power supply current without mounting components such as capacitors in order to suppress radiation noise. It is to provide a manufacturing method thereof.

[0015]

That is, in the wiring board of the present invention, a through hole is formed in an insulating layer, a first wiring extends in the through hole, and a second wiring extends in the through hole. Are extended, and a dielectric is interposed between the extended portions of the first wiring and the second wiring.

Further, in the method of manufacturing a wiring board according to the present invention, a step of forming a first through-hole penetrating from one surface to the other surface in the insulating layer; Extending into the through-hole, filling the first through-hole with a dielectric, forming a second through-hole in the filled dielectric along the first through-hole, Forming an extension of the second wiring from the other surface side in the second through-hole.

As described above, in the wiring board according to the present invention, the first wiring and the second wiring extending in the through hole of the insulating layer and the dielectric material interposed between these extending portions are provided. Therefore, a capacitor can be substantially formed by the first and second wirings and the dielectric, and a conventional technique (for example, a conventional wiring board manufacturing technique) can be used without mounting a capacitor as a component as in the past. Photo etching, chemical vapor deposition,
The area of the current loop can be reduced by simply using sputtering, machining, or the like, and noise can be effectively suppressed.

Further, according to the method of manufacturing a wiring board of the present invention, as described above, a step of forming a first through hole in an insulating layer;
A first wiring extending step for the through-hole, a dielectric filling step for the through-hole, a second through-hole forming step for the filling, and a second wiring extending for the second through-hole Since the method includes the steps described above, it is possible to manufacture a wiring board having the above-described excellent effects at low cost using the conventional printed circuit board manufacturing technology without technical difficulty.

[0019]

In the present invention, it is preferable that the first wiring is a power wiring and the second wiring is a ground wiring. In addition, it is preferable to apply a through-hole plating method for forming the extending portion of the first wiring.

Further, in the present invention, the insulating layer is an insulating substrate, the power supply wiring extends along a wall surface of the first through hole, and a conductor connected to the ground wiring extends along the wall surface. It is preferable that the dielectric is buried in the second through-hole and filled between the extended portion of the power supply wiring and the conductor.

In this case, it is preferable that the extended portion of the power supply wiring is provided in a cylindrical shape on the wall surface of the through hole, and the conductor is arranged at the center of the tubular extended portion.

In the present invention, the ground wiring is provided on the wiring board, the through-hole extending the power supply wiring is provided on the insulating substrate, and the wiring board is insulated from the wiring board as the insulating substrate. It is preferable that they are bonded via a material.

Hereinafter, the present invention will be described more specifically based on the illustrated embodiment.

FIG. 1 shows a wiring board according to an embodiment of the present invention. The wiring board comprises a multilayer wiring board 1 and a two-layer wiring board 3 on which an insulating layer 2 such as a prepreg is interposed. Are laminated.

The multilayer wiring board 1 has a structure in which a ground wiring 5 is formed as a conductor on the surface of the insulating layer 4 and a plurality of conductive layers are laminated in the insulating layer 4 although not shown.
In the two-layer wiring board 3, power supply wirings 7 are formed as conductive layers on the front and back surfaces of the insulating layer 6 in a desired pattern.

A via (through hole) 8 is formed in a predetermined portion of the two-layer wiring board 3 by machining such as a drill. On the inner wall of the via 8, an extended portion 7a of the power supply wiring 7 is formed by through-hole plating or the like. The inside of the via 8 is filled with a dielectric 10, and a center hole 9 formed by drilling or the like in the dielectric 10 is filled with a conductor 11 such as copper, and an insulating layer 2 such as a prepreg is formed.
And reaches the surface of the ground wiring 5 of the multilayer substrate 1.

Therefore, in the via 8 of the two-layer wiring board 3, the space between the extended portion 7 a of the power supply wiring 7 and the conductor 11 is filled with the dielectric 10, and the lower end of the conductor 11 penetrates the insulator layer 2. It is electrically connected to the ground wiring 5.

The material of the dielectric 10 is preferably a ferroelectric. Specifically, a substance having a relative dielectric constant of 10 or more, for example, alumina or silicon is preferable.

The wiring board of this embodiment has the above configuration, and the extended portion 7a of the power supply wiring 7, the dielectric 10, and the conductor 11 constitute a decoupling capacitor. Even if a capacitor is not mounted, the area of the current loop can be reduced and the radiation noise due to the high-frequency current can be effectively suppressed only by using the ordinary technique applied to the wiring board.

The function as the decoupling capacitor, for example, the capacitance thereof depends on the area (ie, the effective operating area of the capacitor) and the distance between the two wirings 7-11 via the dielectric 11 in the via 8. Can be freely set according to the type of IC or LSI to be used.

The wiring board according to the present embodiment having such excellent effects can be efficiently and economically manufactured by the manufacturing process illustrated in FIG.

First, as shown in FIGS. 2A-1 and 2A-2, a conductive layer 7 is formed on both sides of the insulating layer 6 as a first step.
A via 8 is formed at a desired position of the substrate 3 where b is formed by machining such as a drill.

Next, as shown in (B-1) and (B-2) of FIG. 2, a plating layer 7c of copper or the like is plated on the wiring 7b of the two-layer wiring board 3 including the inner wall of the via 8. It is formed by a method. The plating layer 7c in the via 8 can be formed by a through-hole plating method. Subsequently, a resist (not shown) is formed at a predetermined position of the plating layer 7c, and an etching process is performed to form a desired wiring pattern.

After doing this, (C-1) and (C-1) in FIG.
As shown in -2), the rear surface side of the two-layer wiring board 3 is arranged on a flat table 13 to block the lower end opening of the via 8, and the resist 14 covers the opening other than the upper end opening of the via 8 on the power supply wiring side.
A paste-like dielectric 10 is pressed into the inside of the via 8 and filled. In this case, it is preferable to perform a squeegee or the like on the front side of the two-layer wiring board 3 using, for example, a rubber spatula 15 or the like.

When the dielectric material 10 is solidified, (D-
As shown in (1) and (D-2), an insulator 2 such as a prepreg is bonded or bonded to the back surface of the two-layer wiring board 3 and a small diameter drill or the like is applied to the dielectric 10 by using a small-diameter drill or the like.
A central hole 9 is formed on the back side of the insulator 2 so as to pass therethrough.

Subsequently, (E-1) and (E-2) of FIG.
As shown in (2), the multilayer wiring board 1 is bonded or bonded to the insulator 2 on the ground wiring 5 side, a resist (not shown) is formed at a predetermined position, and then a paste-like conductor 11 such as copper is filled. And solidify it. As a result, the conductor 11 is connected to the ground wiring 5, and the dielectric 10
To the extension 7a of the power supply wiring 7 via the.

As is clear from the above, according to the steps of the illustrated embodiment, the present invention can be easily and efficiently performed at low manufacturing cost without technical difficulties by using a general printed circuit board manufacturing technique. A wiring board according to the invention can be manufactured.

The embodiments described above can be variously modified based on the technical idea of the present invention.

For example, in the wiring board of the present invention, there is no need to restrict the materials and the number of the conductive layers and the insulating layers, the forming method thereof, the pattern formation, and the like.

As shown in FIG. 4, for example, a rectangular via 8
The through-hole plating layers in the power supply side 7a and the ground side 7
and the ground side 7 d can be connected to the ground wiring 5 of the wiring board 1 by the conductive adhesive 15. In this case, the conductor 11 as shown in FIG. 1 becomes unnecessary, and the process of forming the capacitor can be further simplified.

FIG. 5 shows an example in which a plurality of, for example, two capacitor structures as shown in FIG. 1 are connected in parallel between a power supply and a ground. In this example, the material of the dielectric 10 can be variously selected, including a material having a low relative dielectric constant.

Further, the capacitance of the via capacitor provided in the insulating layer is changed by changing the facing area and the facing distance between the dielectric and the conductor (wiring) to be filled therein, and the relative permittivity of the filled dielectric. Can be adjusted as desired, and can be set freely according to the type of IC or LSI used.

Further, in the above-described embodiment, the power supply wiring and the ground wiring are extended in the via. However, the present invention is not limited to this. In general, any wiring having a potential difference can be extended in the via. .

[0044]

According to the present invention, the first wiring and the second wiring extend in the via formed in the insulating layer of the wiring board.
Since a dielectric is interposed between these extending portions, the extending portions of these wirings and the dielectric therebetween can exhibit a function as a decoupling capacitor. As a result, the area of the current loop described above is reduced. It is possible to reduce the size and effectively suppress noise.

Therefore, there is no need to mount a capacitor or the like as a component as in the conventional wiring board.
Further, it is possible to sufficiently cope with a case where it is desired to flatten the surface layer of the wiring board.

Since the wiring board of the present invention has the above-described structure, as is apparent from the above-described steps, it is possible to use a normal wiring board manufacturing technique at low cost without technical difficulty. Can be manufactured.

[Brief description of the drawings]

FIGS. 1A and 1B schematically show a wiring board according to an embodiment of the present invention, in which FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view along line XX of FIG.

FIG. 2 shows a specific example of a manufacturing process of the wiring board in the embodiment in the order of steps, and shows (A-1), (B-1), and (C-
1) is a plan view, and (A-2), (B-2), and (C-2) are cross-sectional views along line XX.

FIG. 3 shows a specific example of a manufacturing process of the wiring board in the embodiment in the order of steps, wherein (D-1) and (E-1) are plan views, and (D-2) and (E-2) are Xs. It is sectional drawing which follows the X-ray.

4A and 4B schematically show a wiring board according to another embodiment of the present invention, wherein FIG. 4A is a plan view, and FIG. 4B is a cross-sectional view taken along line YY of FIG.

FIGS. 5A and 5B schematically show a wiring board according to still another embodiment of the present invention, wherein FIG. 5A is a plan view and FIG.
It is sectional drawing which follows the -Z line.

FIG. 6 is a schematic diagram illustrating radiation noise of a conventional wiring board.

FIG. 7 is a schematic diagram illustrating radiation noise of another conventional wiring board.

8A and 8B show a conventional multilayer wiring board, wherein FIG. 8A is a plan view and FIG. 8B is a cross-sectional view.

FIG. 9 shows an already proposed multilayer wiring board,
(A) is a plan view and (B) is a sectional view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Multilayer wiring board, 2 ... Insulator, 3 ... Double layer wiring board,
4, 6: insulating layer, 5: ground wiring, 7: power supply wiring, 7
a: power supply wiring extension, 8: via, 9: central hole, 10: dielectric, 11: conductor, 13: flat base

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4E351 AA01 AA06 BB03 BB29 BB31 BB33 BB49 CC06 CC11 DD01 DD41 GG06 5E338 AA03 BB02 BB12 BB25 BB63 BB75 CC01 CC04 CC06 CD03 EE13 5E346 AA12 AA13 BB03 A43 BB11 A0331 BB03 EE01 EE09 FF04 FF18 FF45 GG15 HH01

Claims (14)

[Claims] 1. A through hole is formed in an insulating layer, a first wiring extends in the through hole, and a second wiring extends in the through hole. A wiring board, wherein a dielectric material is interposed between extending portions of the wiring. 2. The wiring board according to claim 1, wherein said first wiring is a power supply wiring, and said second wiring is a ground wiring. 3. The insulating layer is an insulating substrate, the power supply wiring extends along a wall surface of the through hole, and a conductor connected to the ground wiring is embedded in the through hole along the wall surface. 3. The wiring board according to claim 2, wherein the dielectric is filled between the extended portion of the power supply wiring and the conductor. 4. The wiring board according to claim 3, wherein an extended portion of the power supply wiring is provided in a cylindrical shape on a wall surface of the through hole, and the conductor is disposed at a center of the tubular extended portion. . 5. The wiring board is provided with the ground wiring, the power supply wiring is extended through the through-hole in the insulating board, and the wiring board and the wiring board as the insulating board are separated by an insulating material. The wiring board according to claim 4, wherein the wiring board is adhered. 6. The wiring board according to claim 1, wherein a capacitor is formed by the extension of the first wiring, the dielectric, and the extension of the second wiring. 7. A step of forming a first through hole penetrating from one surface to the other surface in the insulating layer; and a step of extending a first wiring from the one surface into the first through hole. A step of filling the first through hole with a dielectric; a step of forming a second through hole in the filled dielectric along the first through hole; and a step of filling the second through hole into the second through hole. Forming an extension of the second wiring from the surface side. 8. The power supply line according to claim 1, wherein the first line is a power supply line,
The method according to claim 7, wherein the wiring is a ground wiring. 9. The power supply line extending along a wall surface of the first through-hole, and a conductor connected to the ground line is provided along the wall surface in the second through-hole. 9. The method of manufacturing a wiring board according to claim 8, wherein the dielectric is filled between the extended portion of the power supply wiring and the conductor. 10. The method for manufacturing a wiring board according to claim 9, wherein an extended portion of the power supply wiring is provided in a cylindrical shape on a wall surface of the through hole, and the conductor is disposed at the center of the tubular extended portion. . 11. The wiring board, wherein the ground wiring is provided, the first through-hole in which the power supply wiring is extended is provided in the insulating substrate, and an insulating material is provided between the wiring substrate and the wiring board as the insulating substrate. The method for manufacturing a wiring board according to claim 10, wherein the wiring board is adhered. 12. The method according to claim 7, wherein the extension of the first wiring is formed by through-hole plating. 13. The method according to claim 7, wherein the extension of the second wiring is formed by burying a conductor. 14. A capacitor is formed by the extension of the first wiring, the dielectric, and the extension of the second wiring.
A method for manufacturing the wiring board according to claim 7.